The retailer is launching the service, which offers same-day delivery in as little as three hours, across the US this year, the company announced Wednesday.

Walmart is charging a flat fee of $9.95 for delivery. The service requires a minimum order of $30.

Customers can get free delivery on their first order, however, with the promo code FRESHCAR.

To find out if the service has expanded to your area, visit Walmart's grocery site. Customers can also order groceries — and use the promo code — through the retailer's app.

Walmart says it will "aggressively" roll out the delivery service to more than 800 stores in 100 metro areas over the next several months, and ultimately reach about 40% of US households by the end of the year.

Walmart is partnering with Uber and other crowdsourced delivery companies to transport groceries to customers' doorsteps.